1. Field of the Invention
This invention relates to boom mounting and control apparatus. More particularly, the invention relates to an apparatus for mounting and controlling the orientation of a boom on a vehicle mounted frame by means of a single hydraulic drive mechanism. The invention is particularly adapted for controlling the operating orientation and extension and retraction of agricultural spray boom assemblies mounted on a tractor by means of a single hydraulic drive on each side.
2. Description of the Prior Art
Agricultural spray booms have been used for a number of years. These booms are generally mounted on a tractor and spray nozzles are positioned along the boom arms. The tractor is then driven across the field as the crops are sprayed. This allows a relatively wide swath to be covered with each pass through the field. Known types of agricultural spray boom assemblies are shown, for example, in U.S. Pat. No. 3,581,993, issued June 1, 1971, to Robert M. Reams and U.S. Pat. No. 3,514,038, issued May 26, 1970 to Alvin E. McQuinn.
Devices of the type shown in the Reams and McQuinn patents use hydraulic mechanisms to either raise and lower the spray boom (Reams) or to longitudinally extend and retract the booms (McQuinn). Other standard hydraulically powered spray booms in the industry utilize one set of hydraulic cylinders to fold the ends of the boom toward the tractor when turning at the ends of a row or when transporting the device from field to field and a second set of hydraulic cylinders to adjust the height of the boom ends to allow for unlevel field conditions. The Reams and McQuinn patents disclose devices that have limited adjustment capability. The other types of known devices which use multiple sets of hydraulic cylinders are costly to manufacture and maintain. Further, the vehicle, such as the tractor, must be equiped with at least four sets of remote cylinders; this is usually not standard equipment on farm tractors.
The present invention provides an apparatus that allows for multiple adjustability of the spray booms while employing only two hydraulic cylinders, one on each side of the tractor. The apparatus of the invention is advantageous in that it can be used with tractors that have as standard equipment two hydraulic take-offs, it is less expensive to manufacture and operate since it only employs two hydraulic drives, and it is easier to operate because only one control lever is needed per side (rather than the two control levers per side required with a four cylinder unit).